Build Your Own Z80 Computer: Design Guidelines and Application (1981) | Hacker News Reader

Build Your Own Z80 Computer: Design Guidelines and Application (1981)

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104 pointsmariuz28 comments

Steve Ciarcia’s Byte magazine articles are a great read (in fact all of Byte was great) - being enthralled by them as a kid but not understanding them probably had a large effect on me choosing to study electronics.

https://archive.org/details/BYTE-MAGAZINE-COMPLETE

same here!

From the comments on the archive.org details, that archive is missing years, the original source of the scans is http://vintageapple.org/byte , and it has all of them

Thanks for that!

My mom subscribed to Byte magazine, and Ciarcia's articles were inspiring to me too. That, and Goedel, Escher, Bach. Oddly enough I ended up at a college with no engineering program, but my physics professor was an electronics expert, and I majored in math and physics. Since then, virtually everything I've done with physics has involved electronics and computers, often working together.

Radio Shack had a book on the Z80, that I think was the same as the Howard Sams book, but with a different cover. It was so clearly written, that even to this day, my ability to conceptualize the innards of computers is strongly biased by the Z80 architecture.

Written by Steve Ciarcia, it's indeed a very good book.

If I am not mistaken a Youtuber made this popular again so second hand copies go for $100+.

Grab the PDF while you can....

What YouTuber? I'd like to subscribe.

Probably Ben Eater

I subscribed to Byte magazine when I was in high school and college, and I owned this book. When I graduated with a BSEE degree in 1985, I designed my own Z80 computer but used this book as a reference. However, just before I started buying parts, I realized a 68000 microprocessor wasn't that much more expensive, so I went that route and built it. I never did anything with the it, but it was a fun exercise.

I imagine you booted it at least with some small code? The 68k assembly is nice.

I had some "seed" 68K code to work with, and then I augmented it heavily. There was a monitor program that I added features to, including adding an assembler and disassembler. But other than getting the monitor and memory test programs working, adding a clock, and a few small utilities, I never built it up to do anything useful.

I still have the source code: https://thebattles.net/crypt/index.html#68k

Oh wow this brings back memories.. I used to check this book out from a local library from time to time and daydream about building a computer. It would've been outdated already even then, but the idea appealed to me anyways.

I lament that he didn't spend a chapter or two on a floppy disk and floppy disk controller. I would like to see a detail treatise on that, I've never seen one.

Maybe its straightforward, drag and drop from the FDC data sheet into a bit of code. Then again, maybe not.

Even when he did the SB-180, his 64180 based SBC, it has an FDC, but he does not talk of it much.

He also did some articles on an 8088 computer. This was interesting because it came out in that seeming millisecond of time between CP/M and MS-DOS, but before "PC Compatible". His computer could run MS-DOS (or, I reckon, CP/M-86), but it was not a PC Compatible.

But it was just a couple of articles, not a book like this was.

Mind, he spent much of his time in the controller world, not really the desktop world. The SB-180 was a bit of a anomaly in that sense, as it was more of a full desktop machine than most of his other work.

FDCs were tricky things. When reading you had to pick up a byte every 8 usec, when writing you had to be ready with the next byte in the same amount of time, and a whole sector's worth would need to be dealt with without interruption. (Idk if the number was exactly 8 usec, but it was in that neighborhood)

Most of the early 8 bit micros couldn't service an IRQ fast enough to keep up, so you'd be more likely to see a polling loop, but even those had to cut things tight. I saw some 1.7MHz 6809 code that could just about do it. Not sure how the old TRS80s dealt, maybe LDI type things? I know the IBM 5150 relied on a DMA chip to shift the sectors to/from disk. Would be fun to find out what the old S-100 systems did.

I used to have this book and loved it. Kid me could never have built this. Adult me couldn't either, but the idea that somebody could was pretty extraordinary.

Great book, and one I used for my own homebrew Z80 project

https://www.jake-reich.co.uk/zx-jakey

Just one chapter in — and I already love the linear power supply.

The 68k processor equivalent of this is Alan Clement's "Microprocessor Systems Design: 68000 Family Hardware". Sadly, the few years the 68k on the Z80 meant that the designs were necessarily more complex, e.g. how 68k bus cycles worked, more integrated parallel/serial interfaces, etc. IIRC there was even a small detour into MMUs, which must have been inconceivable for a home-brew computer then.

Interesting, I was just yesterday researching more about Z80 after seeing some cheap refub chips on AliExpress. I might order some and try to follow this guide

If you visit https://www.tindie.com/ you can search for either "Z80" or "CP/M" and find a lot of single-board computers that are available as kits.

RC2014 is the most popular, a modular system with lots of options, but that's overkill and more expensive than it needs to be if you just wanna get a simple system working and running your own code.

Check out http://www.searle.wales/

Does anyone build their own computers from motherboards and other electronic components these days, say by soldering them on, or connecting them into slots?

I don't have the background to do it, and not planning to, but am just interested to know. I used to read the Steve Ciarcia's Circuit Cellar column in BYTE long ago, just out of interest, even though I didn't have any knowledge of electronics.

Hoo yep:

https://z80kits.com/product-category/basekits/

https://smallcomputercentral.com/

https://j4f.info/start

http://www.searle.wales/

To name a few.

Steve's book is fascinating and a good intro to the architecture, but some of the chips used are quite obsolete (even more so that the mainstream obsolete ones!) and so building a computer from that book would be very challenging.

Huge shout out to Small Computer Central/Steven Cousins. I have four or five machines designed by him, with various main boards and backplanes. The parts are all tested working, and the build instructions are comprehensive. It’s a very enjoyable project to go from a pile of parts to connecting to the UART and blinking some LEDs.

I think doing a breadboard like 6502 would be interesting and would be my next side project. Not sure this count: https://bread80.com/2020/07/24/couch-to-64k-a-k-a-building-a...

Before the Speccy got famous, I remember seeing such kind of Z80 building kits on electronic hardware stores on my small Portuguese town.

(1981)

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